Drafting pen with vent valve



E. BOK

DRAFTING PEN WITH VENT VALVE Aug. 26, 1969 2 Sheets-Sheet 1 Filed Sept. 11, 1968 arra /$16" 2 Sheets-Sheet 2 Aug. 26, 1969 BQK DRAFTING PEN WITH VENT VALVE Filed Sept. 11, 1968 ....,...li I llv I! WW x mw A i u wa w.w 747/! My? I -"f-r- United States Patent Int. Cl. B43k /18 U.S. Cl. 401-259 Claims ABSTRACT OF THE DISCLOSURE A stylographic drafting pen of the type having a cylindrical hard metal tip communicating with a vented ink reservoir, particularly a pressurized valve for the reservoir vent, so as to regulate the amount of air admitted to the reservoir and thus regulate ink flow.

BACKGROUND OF THE INVENTION Field of the invention The drafting pen is characterized in that it has a valve in the top of the ink cartridge, which valve is only operable through a displacement of it against the force of a pressure spring, and which displacement is achieved with the aid of a side knob which protrudes through a slot in side wall of the pen barrel and which knob is longitudinally movable in the slot by the forefinger of the hand that holds the drafting pen.

The knob construction also serves for the angular locking of the ink cartridge within the barrel.

As the writing pen tip assembly, which is attached to the bottom part of the barrel has an angular surface complementally engaging the ink reservoir interior, the pen tip therefore can only slide longitudinally within the ink cartridge, a simple, but very useful means is obtained to get the pen tip always in the same position with respect to the knob.

The ink reservoir also longitudinally is secured to the barrel, enabling easy filling of this ink reservoir if the writing pen tip is only removed from the barrel.

Description of the prior art Stylographic drafting pens are often used to draw lines on sheets of paper. Conventional drafting pens thereby have to be kept in a vertical position on such a sheet during the drafing of lines. In Patent No. 3,419,335, entitled Drafting Pen, and issued to applicant herein Dec. 31, 1968, a drafting pen is described whereby it is possible to have the drafting pen placed on the sheet at an angle which is most suitable for the draftsman. This pen included the combination of a pen tip and a guide or support which rested on the drafting sheet. Consequently, the pen tip was supported at an angle to the paper and the radial position of the pen tip with respect to the barrel was fixed.

In some drafting work this more expensive construction is not required, especially if the quality of the drawn lines is of not too great importance. The possibility of supporting a drafting pen in a given radial position and with only the pen tip resting upon the drafting papers provides a big advantage over the existing drafting pens.

Furthermore, conventional stylographic drafting pens and also the drafting pen as it is described in the aforementioned Patent No. 3,419,335 make use of a vent construction to the ink cartridge which is positioned in the bottom part of the pen underneath the ink cartridge. See Patent No. 2,891,512. In this type vent there are the dis advantages of an easy clogging with dried ink in the vent 3,463,598 Patented Aug. 26, 1969 ice opening and the leakage of ink through the opening in the pen tip.

Other vent constructions are illustrated in Patents Nos. 1,319,556 and 1,457,875 describing stylographic fountain pens, which are not suitable for drafting straight lines, since the flow of ink around the pen tip is not tolerated when using a ruler.

Patent 3,333,576 has an expensive buildup for a low priced drafting pen, having a pressurized seat for activating a cleansing wire in the absence of any valving for the air vent.

SUMMARY OF THE INVENTION According to the present invention regulation of air admitted to the ink reservoir is controlled by a spring pressurized stern which overrides the reservoir within the pen barrel. The stem includes an axially positioned valve which moves into and out of the reservoir vent, as a control gnob is moved by the draftsmans index finger grasping the barrel. Consequently, ink flow can be controlled without lifting of the drafting pen from the paper or other interruption. Both the stem, reservoir and cleaning wire lead weight are locked against twisting or turning within the barrel.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of stylographic drafting pen according to the invention with the vent valve in an opera position;

FIG. 2 is an enlarged longitudinal sectional view of the drafting pen according to FIG. 1 with the vent valve in a closed position;

FIG. 3 is an enlarged fragmentary longitudinal sectional view of the drafting pen according to the FIGS. 1 and 2 showing again the vent valve in the open position;

FIG. 4 is an enlarged longitudinal sectional view of the writing nib plug assembly being separated from the holder assembly;

FIG. 5 is a transverse sectional view of the holder assembly along section line 5-5 of FIG. 3; and

FIG. 6 is a transverse sectional view of the drafting pen along section line 6-6 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 drafting pen 10 is shown as being held by the hand 12 in an angular position with respect to drafting sheet 14. Ink line 16 is being produced, while at the same time the forefinger 18 via a longitudinal movement of the knob 20 and the stem 22 has lifted the vent valve 24 from the valve seat 26 of the ink cartridge 28 and air ventilation is made possible through the opening 30 in the top 32 of said cartridge.

In vent valve open position the knob 20 is thus forced against the pressure of spring 34 towards the notch 36 (see also the other figures) of the slot 38 of the barrel 40.

In vent valve closed position if the knob 20 is released by the forefinger 18, this knob 20 then moves under the force of the light compression spring 34 downwards in the slot 38 towards the notch 42, as is indicated in FIG. 2.

This downward closed position is possible for a long period of time during the drafting of the lines and, as soon as a restricted ink flow through the passageway 44 of the pen tip 46 and onto the paper is noticeable, the knob 20 can be lifted for a short period of "time by means of the upward moving of the forefinger 18, resting upon this knob.

Barrel 40 is in its lower part 48 provided with the internal screw thread 50 (see also FIG. 4) enabling the writing nib assembly 52 to be screwed therein. The writing nib assembly 52 mainly consists of the writing nib 3 54 and the screw plug 56, whereby the nib 54 is locked longitudinally in this plug 56 by means of its nib seat 58, recess 60 in the plug and the lock ring 62 located in the recess 63. The hole 61 in plug 56 serves for the passage of means to remove the lock ring 62 from the recess 63.

The milled edge 64 provides a good hand hold of this plug during its required angular displacements. In the barrel 40 the ink reservoir 28 longitudinally is locked by means of the combination of the bottom ring 66 of the ink cartridge, the recess 68 in the bottom part 48 of the barrel 40 and the lock ring 70 resting on recess 72. Here is provided, also, the hole 73 in the barrel 40 for the passage of means to remove the lock ring 70 from the recess 72.

In between barrel 40 and ink reservoir 28 the holder stem 22 is longitudinally movable, whereby the lateral twisting or turning movement of this stem is made impossible by means of the combination of stem knob 20 and slot 38 of the barrel 40, see also FIG. 6.

In the upper part 74 of the stem 22 the inner-circular profile 76 extends to the non-circular profile 78, which profile 78 corresponds with the profile 80 of the top part 32 of the ink cartridge 28, see also FIG. 5.

Due to the above described construction it is obvious that a lateral twisting or turning of the ink cartridge 40 in the barrel 14 is impossible.

The inside 82 of the ink cartridge 28 is provided with a fiat side 84 which side 84 corresponds with the flat outside 86 of the writing nib 54 in such a way that only longitudinal movement of part 88 of the nib 54 in the inside 82 is possible.

The bottom shoulder 90 of the ink cartridge 28 is provided with the circular interior 92, in which opening the cylindrical part 94 of the writing nib 54 fits complementally and leak free, as illustrated in FIG. 2.

After filling of the barrel 40 with ink 96 being poured into the ink reservoir 28, the nib assembly 52 can be screwed on without an angular displacement of it against barrel 40.

It is possible to provide the pen tip writing end 46 with an angular bottom 98 which angle is about 30, enabling holding of the drafting pen at an angle of about 60 with respect to the drafting sheet.

The lowest surface 100 of this pen tip has such a radial position with respect to knob as is the best for the easiest handling of this knob 20.

Surface 100 can be about 45 degrees radially to the left of knob 20, as is indicated in FIGS. 2 and 6, with the center line 102 being indicated in phantom through this bottom part 100.

Cleaning wire 104 with weight 106 attached thereon can also be provided with an angular bottom part if the combination of wire and weight is to be locked against radial twisting or turning within writing nib 54. Removable lock pin 108 positioned in the top part 110 of the writing nib 54 may serve this purpose.

I claim:

1. A drafting pen comprising:

(A) a pen barrel;

(B) an ink reservoir of the type having an air vent and supported within said barrel;

(C) a pen tip with a writing end point secured at one end of said barrel and including a hollow ink capillary passage communicating with said ink reservoir; and

(D) a spring pressurized stern superposed with respect to said reservoir within said barrel and including:

(i) a valve selectively engageable with said air vent.

2. A drafting pen as in claim 1, said stem being concentrically mounted intermediate said reservoir and said barrel and further including:

(i) a valve head axially aligned with said vent and (ii) a side knob attached to said stem.

3. A drafting pen as in claim 2, said pen tip being locked against lateral turning movement within said barrel and including:

(i) a weight with a cleansing wire independently seated within said tip and extending through the writing end point.

4. A drafting pen as in claim 3, said pen tip writing end being inclined, so as to permit angular support of said pen with respect to a drafting surface.

5. A drafting pen as in claim 4, said stem further including:

(i) a compressing spring interposed between said stem and said barrel so as to urge said stem and valve against said reservoir within said barrel, in nonventing position and said spring being compressible upon reciprocation of said side knob to vent said ink reservoir.

6. A drafting pen as in claim 5, said ink reservoir being open at its bottom end so as to complementally receive an inner end of said pen tip and said barrel, including a lock collar threadedly locking said pen tip to said barrel.

7. A drafting pen as in claim 6, including means locking said weight against lateral turning within said pen tip.

8. A drafting pen as in claim 7, said ink reservoir having at least one fiat interior portion and said pen tip having at least one complementary fiat exterior portion, said flat portion abutting and locking said pen tip against lateral turning within said ink reservoir.

9. A drafting pen as in claim 2, said side knob extending from said stem through said pen barrel.

10. A drafting pen as in claim 7, said cleaning wire end extending through said writing end point being inclined in parallel with said pen tip writing end, so as to permit angular support of said pen and protruding wire end with respect to a drafting surface.

References Cited UNITED STATES PATENTS 748,383 12/ 1903 Langill 401--260 1,011,800 12/ 1911 Jackson 401-276 1,576,909 3/1926 Hearn 401276 X 3,020,884 2/1962 Riepe et a1. 401259 3,247,828 4/1966 Basham 401-260 X 3,333,576 8/1967 Exner 401-104 LAWRENCE CHARLES, Primary Examiner 

